Hi everyone – I thought to share with the community my recent experience with a Sweetheart lychee in Miami Beach as a backyard grower hoping that it may be useful to other fellow growers who were frustrated – like me – with this tree finicky behavior especially considering the scant information on this newly introduced variety.
I bought this specimen at PIN 3.5 years ago and it grew to become a beautiful and healthy 8 foot tall tree with a full round canopy. As the tree never bloomed I thought to reach out to 2 other backyard growers in my neighborhood and listen to their experience. Feedback was not very encouraging. Their trees - both over 15 years old - never bloomed with 1 exception – 2010 – when a more serious cold front hit Miami and the Beach. That year they had a bumper crop. Nothing since then.
The Beach is a more difficult growing environment for lychees due to the difficulty of getting sufficient chill hours. It is common knowledge that the Beach is consistently warmer than Miami due to its exposure to both the Ocean and the bay which act as insulators.
As a last resort I decided to follow lycheesonline recommendations and see whether I could bring the tree to bloom through human intervention. Here is what I did. 1) Stopped fertilizing the tree in July. 2) Pruned in August. 3) Girdled in October. The weather helped too with a colder winter.
The tree is now blooming. And this may not sound like big news considering this year’s weather. What I found relevant is that only and exclusively the canopy impacted by girdling is developing panicles. I counted 19 of them. The rest of the tree does not have a single panicle.
Lycheesonline reports: “Don't be surprised when the girdled branch(s) is loaded with fruit and the rest of the tree fruits lightly. The fruiting of the non-girdled branch is typical of what the tree would have produced had you not girdled the tree at all”.
This means that without girdling my tree would not have bloomed at all.I must conclude that in my case girdling was not just a bloom booster, as many articles report, but rather
the critical step to trigger blooming.
This said I doubt girdling would be able to induce blooming with average temp of 70F. But in borderline situations - meaning when you get close to the chill requirement but not quite - girdling may be able to give your tree the extra boost to do just that.
Now I know that even with 55 average temp in February (this is the reported temp in Miami Beach for this month) my Sweetheart would not bloom (unless I girdle it). Whereas Mauritius - based on my Neighbor’s experience in 2010 - would bloom without human intervention. So Sweetheart appears to be less reliable than Mauritius based on this specific comparison (which is however only 1 data point and therefore far from being conclusive). Being my tree only 3.5 I realize there may be a juvenile factor to be considered and as the tree matures it may be able to bloom in conjunction with slightly higher temperatures.
My Neighbor’s tree, a large Mauritius – see third picture - is blooming too this year (the way it did in 2010 without any human intervention). He is in the ice business and this year, for the first time, has applied 100 pounds of ice daily for 14 days in a row. I do not think we can draw a clear conclusion on the efficacy of ice applications. There is research out there suggesting that cooling roots only is not sufficient. Besides Mauritius is described as a more reliable variety for south east Florida. If you add to that the fact that we had a cooler winter on the Beach this year than we did in 2010 I think it is reasonable to think that it would have bloomed no matter what. Below I report the average temperatures in Miami Beach in the last 6 years.
Nov Dec Jan Feb
season 2009 71 70 67 66
season 2010 75 72 60 62
season 2011 73 60 66 70
season 2012 75 73 69 72
season 2013 72 73 74 72
season 2014 76 70 67 73
season 2015 72 70 70 55

